[Qemu-devel] [RFC v2 01/11] tcg: move tb_invalidated_flag to CPUState

[Alex Bennée]

From: Paolo Bonzini <address@hidden>

This is a baby step towards making tb_flush thread safe.

Signed-off-by: Paolo Bonzini <address@hidden>
Signed-off-by: Sergey Fedorov <address@hidden>
[AJB: use bool]
Signed-off-by: Alex Bennée <address@hidden>

---
v2
  - use bool properly
---
 cpu-exec.c              | 11 +++++------
 include/exec/exec-all.h |  2 --
 include/qom/cpu.h       |  2 ++
 translate-all.c         |  6 ++----
 4 files changed, 9 insertions(+), 12 deletions(-)

diff --git a/cpu-exec.c b/cpu-exec.c
index 3694234..74065d9 100644
--- a/cpu-exec.c
+++ b/cpu-exec.c
@@ -205,10 +205,11 @@ static void cpu_exec_nocache(CPUState *cpu, int 
max_cycles,
     if (max_cycles > CF_COUNT_MASK)
         max_cycles = CF_COUNT_MASK;
 
+    cpu->tb_invalidated_flag = false;
     tb = tb_gen_code(cpu, orig_tb->pc, orig_tb->cs_base, orig_tb->flags,
                      max_cycles | CF_NOCACHE
                          | (ignore_icount ? CF_IGNORE_ICOUNT : 0));
-    tb->orig_tb = tcg_ctx.tb_ctx.tb_invalidated_flag ? NULL : orig_tb;
+    tb->orig_tb = cpu->tb_invalidated_flag ? NULL : orig_tb;
     cpu->current_tb = tb;
     /* execute the generated code */
     trace_exec_tb_nocache(tb, tb->pc);
@@ -229,8 +230,6 @@ static TranslationBlock *tb_find_physical(CPUState *cpu,
     unsigned int h;
     tb_page_addr_t phys_pc, phys_page1;
 
-    tcg_ctx.tb_ctx.tb_invalidated_flag = 0;
-
     /* find translated block using physical mappings */
     phys_pc = get_page_addr_code(env, pc);
     phys_page1 = phys_pc & TARGET_PAGE_MASK;
@@ -303,6 +302,7 @@ static TranslationBlock *tb_find_slow(CPUState *cpu,
 #endif
 
     /* if no translated code available, then translate it now */
+    cpu->tb_invalidated_flag = false;
     tb = tb_gen_code(cpu, pc, cs_base, flags, 0);
 
 #ifdef CONFIG_USER_ONLY
@@ -509,12 +509,11 @@ int cpu_exec(CPUState *cpu)
                 tb = tb_find_fast(cpu);
                 /* Note: we do it here to avoid a gcc bug on Mac OS X when
                    doing it in tb_find_slow */
-                if (tcg_ctx.tb_ctx.tb_invalidated_flag) {
+                if (cpu->tb_invalidated_flag) {
                     /* as some TB could have been invalidated because
-                       of memory exceptions while generating the code, we
+                       of a tb_flush while generating the code, we
                        must recompute the hash index here */
                     next_tb = 0;
-                    tcg_ctx.tb_ctx.tb_invalidated_flag = 0;
                 }
                 /* see if we can patch the calling TB. When the TB
                    spans two pages, we cannot safely do a direct
diff --git a/include/exec/exec-all.h b/include/exec/exec-all.h
index 6151a62..bbd9807 100644
--- a/include/exec/exec-all.h
+++ b/include/exec/exec-all.h
@@ -302,8 +302,6 @@ struct TBContext {
     /* statistics */
     int tb_flush_count;
     int tb_phys_invalidate_count;
-
-    int tb_invalidated_flag;
 };
 
 void tb_free(TranslationBlock *tb);
diff --git a/include/qom/cpu.h b/include/qom/cpu.h
index b7a10f7..6931db9 100644
--- a/include/qom/cpu.h
+++ b/include/qom/cpu.h
@@ -238,6 +238,7 @@ struct kvm_run;
  * @crash_occurred: Indicates the OS reported a crash (panic) for this CPU
  * @tcg_exit_req: Set to force TCG to stop executing linked TBs for this
  *           CPU and return to its top level loop.
+ * @tb_invalidated_flag: Set to tell TCG that tb_flush has been called.
  * @singlestep_enabled: Flags for single-stepping.
  * @icount_extra: Instructions until next timer event.
  * @icount_decr: Number of cycles left, with interrupt flag in high bit.
@@ -289,6 +290,7 @@ struct CPUState {
     bool stopped;
     bool crash_occurred;
     bool exit_request;
+    bool tb_invalidated_flag;
     uint32_t interrupt_request;
     int singlestep_enabled;
     int64_t icount_extra;
diff --git a/translate-all.c b/translate-all.c
index 56498e0..d923008 100644
--- a/translate-all.c
+++ b/translate-all.c
@@ -841,6 +841,7 @@ void tb_flush(CPUState *cpu)
     tcg_ctx.tb_ctx.nb_tbs = 0;
 
     CPU_FOREACH(cpu) {
+        cpu->tb_invalidated_flag = true;
         memset(cpu->tb_jmp_cache, 0, sizeof(cpu->tb_jmp_cache));
     }
 
@@ -1009,12 +1010,11 @@ void tb_phys_invalidate(TranslationBlock *tb, 
tb_page_addr_t page_addr)
         invalidate_page_bitmap(p);
     }
 
-    tcg_ctx.tb_ctx.tb_invalidated_flag = 1;
-
     /* remove the TB from the hash list */
     h = tb_jmp_cache_hash_func(tb->pc);
     CPU_FOREACH(cpu) {
         if (cpu->tb_jmp_cache[h] == tb) {
+            cpu->tb_invalidated_flag = true;
             cpu->tb_jmp_cache[h] = NULL;
         }
     }
@@ -1176,8 +1176,6 @@ TranslationBlock *tb_gen_code(CPUState *cpu,
         /* cannot fail at this point */
         tb = tb_alloc(pc);
         assert(tb != NULL);
-        /* Don't forget to invalidate previous TB info.  */
-        tcg_ctx.tb_ctx.tb_invalidated_flag = 1;
     }
 
     gen_code_buf = tcg_ctx.code_gen_ptr;
-- 
2.7.4